1. Field of the Invention
This invention is related to matable electrical connectors in which spring beam terminals in one of the connectors are deflected prior to mating engagement with terminals in the other connector to reduce the mating force and to enhance the durability of the terminals and of the plating on the terminals.
2. Brief Description of the Prior Art
Zero insertion force (ZIF) or low insertion force (LIF) electrical connectors or sockets typically employ some form of cam member to reduce or eliminate the insertion force as two electrical connectors are mated. These connectors are typically used to reduce or eliminate the frictional force between mating male and female terminals. This frictional or mating force can result in damage to the terminals and to the electroplating used to ensure an good electrically conductive interface. High mating forces can also reduce the number of mating and unmating cycles for which specific terminals can be employed. Terminals and connectors that have distinct advantages for certain applications cannot be used for potentially related applications in which the connectors must be mated or unmated more frequently because of damage to the mating interface. Conventional ZIF or LIF connectors have been used in applications of this type, but one problem is that prior art ZIF or LIF connectors require a separate camming member that must be actuated as an additional step in the mating and unmating process. These additional camming members and rotary or linear actuators also add an additional component requiring additional space and generally resulting in additional cost.
Many prior art ZIF or LIF electrical connectors are used in sockets for integrated circuit components. Others are used to connect wires to pins on printed circuit boards. U.S. Pat. No. 4,350,402 discloses one such board mounted zero insertion force electrical connector in which female terminals are located in an inner housing and an outer housing includes inclined actuating surfaces for spreading the contact beams when the outer housing is shifted relative to the terminals and to the inner housing. A linear cam is used to impart movement between the two housings resulting in separation of opposed contact arms. U.S. Pat. No. 4,067,633 also employs two shiftable housings and inclined contact actuating surfaces on the housing that moves toward the mating ends of the spring contacts. This latter connector employs external handles on the connector attached to wires. When these handles are pressed together the terminals are moved forward to spread the contacts so that pins on a printed circuit board can be inserted between the contact arms without significant frictional mating force. One problem with this approach is that the terminals can still be forced into engagement with the pins without first separating the female spring beam, thus resulting in damage to the contact interface.
Each of these prior art approaches requires and additional cam actuating step to mate the connectors. U.S. Pat. No. 4,655,526 discloses another low insertion force electrical connector in which spring beams are initially held in a partially open position and are then released when two connectors are mated. However, this approach requires a complicated contact structure including insertion of a coil spring between spring beams. This contact structure differs significantly from standard contacts that have proved reliable in may applicatons.
Another approach is to partially preload spring beam terminals so that the mating force is reduced. An example of one such approach is shown in U.S. Pat. No. 4,685,886. Although this approach has advantages it eliminates only part of the mating force and it is typically used to reduce mating force to insure complete connection and not necessarily to increase the number of mating cycles.
The instant invention overcomes many of these disadvantages by providing an electrical connector in which mating force is significantly reduced in a configuration in which the connectors are mated by simply inserting one connector into another without manipulation of a separate cam actuator. This invention permits standard female or receptacle terminals, that are typically intended to be used for a limited number of mating and unmating cycles to be employed in applications requiring many more mating cycles. One of the objects of this invention is to permit standard receptacle terminals that are commonly used in automotive applications as input and output terminals for attaching other components or appliances to the vehicle electrical system. For example, this approach will allow portable electronic devices to be repeatably connected and disconnected to an electronic bus in the vehicle. Another object achieved by invention is to provide this capability without significant cost disadvantages and without requiring numerous additional components while still being relatively easily molded.
The advantages of this invention are also not limited to motor vehicle applications. This invention can be employed in numerous applications including printed circuit board connectors, integrated circuit component sockets, and wire to wire connectors.
One especially significant advantage of this invention is that the two connectors cannot be mated or unmated without first deflecting spring beam terminals so that male terminals can be inserted or removed without damage to the contact interface and to the plating on the terminals.
This electrical connector assembly also incorporates by a cam actuation function and a connector latching function. Disengagement of the connector latch also separates the terminal mating interface so that the connectors can be unmated without damage to the terminals.
These and other advantages are achieved by an electrical connector assembly including first and second mating electrical connectors. The first electrical connector includes first and second housings and female terminals. The first housing includes cavities with the female terminals secured in the cavities and a deflectable camming lever. The second housing includes camming surfaces engageable with the female terminals to open the female terminals. The second electrical connector includes a mating housing and male terminals insertable into mating engagement with the female terminals. The mating housing includes a surface engagable with the camming lever during mating to deflect the camming lever and shift the second housing relative to the first housing and open the female terminals for insertion of the male terminals.
The first electrical connector has a molded housing with a molded latch engagable with the second electrical connector to latch the connectors in a mating position. The molded latch includes a camming surface for shifting a portion of the first electrical connector relative to the molded housing as the first and second electrical connectors are mated.
The first electrical connector of this assembly has a front mating face and a rear face. The terminals in this first connector have a deflectable spring contact section. A rear housing in this first connector includes cavities in which the terminals are secured. A front housing telescopes relative to the rear housing between a first forward and a second relative rearward position. The front housing has a front panel with a plurality of openings and camming projections on an interior surface of the front panel located adjacent the openings and facing rearward. A camming member is located adjacent to the front mating face of the connector. Deflection of the camming member brings the camming member into engagement with the front housing and moves the front housing toward the second relative rearward position and toward the contacts to bring the camming projections into engagement with the spring contact sections to deflect the spring contact sections. The second electrical connector includes a housing abutting the camming member when mated with the first electrical connector to deflect the camming member to cause deflection of the spring contact sections.